The present invention relates to improvements in a refrigerated showcase that is used in a supermarket or the like.
In a heretofore known refrigerated showcase shown in FIGS. 1 and 2, a refrigerator (3) and a fan (4) are contained within a duct (2) for circulating refrigerated air to refrigerate fresh and/or refrigerated goods displayed in the showcase, which duct is provided in the bottom wall (1) of the showcase. The front end of the duct (2) communicates with an intake port (5) at the bottom edge of a front opening of the showcase, and the rear end of the duct (2) extends vertically in the rear wall (6) of the showcase, further extends through the top wall (7) of the showcase and communicates with a blow-out port (8) at the top edge of the front opening of the showcase.
Outside of and extending parallel to the duct (2) are ducts (2') and (2") for circulating cold air to prevent a temperature rise in the refrigerated air for refrigerating the fresh and/or refrigerated goods displayed in the showcase. The front ends of the respective ducts (2') and (2") communicate with intake ports (5') and (5") at the bottom edge of the front opening of the showcase, the rear ends of the ducts (2') and (2") extend through the rear wall (6) of the showcase and the top wall (7) of the showcase and communicate with blow-out ports (8') and (8") at the top edge of the front opening of the showcase, and fans (9) and (10) are provided within the respective ducts (2') and (2").
Accordingly, the refrigerated air for refrigerating the interior of the showcase, which has been sucked into the duct (2) by the fan (4) and refrigerated by the refrigerator (3), passes through the duct (2) provided in the bottom wall (1), rear wall (6) and top wall (7) of the showcase, then it is blown out of the blow-out port (8) at the top edge of the front opening of the showcase and sucked into the intake port (5) at the bottom edge of the front opening, and while the refrigerated air circulates across the front opening of the showcase and through the rear wall (6) and top wall (7) of the showcase, it refrigerates the fresh and/or refrigerated goods (12) placed on shelves (11) within the showcase and on the bottom wall (1).
On the other hand, the air sucked into the ducts (2') and (2") through the intake ports (5') and (5") at the bottom edge of the front opening by the fans (9) and (10), is cooled by the refrigerator (3) and the refrigerated air in the duct (2) while it flows through the bottom wall (1), rear wall (6) and top wall (7), is then blown out of the blow-out ports (8') and (8") at the top edge of the front opening of the showcase, and forms a low-temperature air curtain outside of the flow of the refrigerated air for refrigerating the interior of the showcase at the front opening of the showcase so that the refrigerated air for refrigerating the interior of the showcase does not come into direct contact with the ambient air and rise in temperature.
However, even if the invasion of the ambient air into the showcase is prevented by the above-described air curtain, the ambient air would mix with the air curtain and the refrigerated air for refrigerating the interior of the showcase as shown by arrows A, and thereby the refrigerating effect is degraded at the lower shelves in the showcase as compared to the higher shelves.
In order to prevent such degradation of the refrigerating effect in the lower portion of the showcase, as shown in FIG. 3, a somewhat improved refrigerated showcase was proposed in which refrigerated air blow-out ports (13) are open in the rear wall (6) of the showcase to introduce the refrigerated air directly into the interior of the showcase. In FIG. 3, component parts which are equivalent to those provided in the refrigerated showcase shown in FIGS. 1 and 2, are given like reference numerals.
However, in the last-mentioned improved case, although the refrigerating effect for the interior of the showcase is improved, upon defrosting the refrigerator (3), the air at an elevated temperature would invade the interior of the showcase through the above-mentioned blow-out ports (13) as shown by arrows B, and would come into direct contact with the fresh and/or refrigerated goods (12), resulting in deterioration of the quality of the goods. In FIG. 4 which shows a defrosting state of the same refrigerated showcase, reference numeral (14) designates a heater in an operating state.